Reciprocating rotary arthroscopic surgical instrument

ABSTRACT

A surgical instrument includes a cutting member with an implement for cutting tissue, and a drive coupled to the cutting member to simultaneously rotate and translate the cutting member in response to a three applied to the drive. A method of cutting tissue includes positioning an outer member such that tissue is located within the outer member, engaging the tissue with an inner member, and simultaneously rotating and translating the inner member to cut the tissue. A tangential cutting force is applied to the tissue with the inner member to mechanically cut the tissue. The inner member is mechanically driven to undergo simultaneous rotation and translation.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/734,674, filed Apr. 12, 2007, now allowed, which is a continuation ofU.S. application Ser. No. 09/983,810, filed Oct. 26, 2001 now U.S. Pat.No. 7,226,459. The prior applications are incorporated herein byreference in their entirety.

TECHNICAL FIELD

This invention relates to rotary cutting surgical instruments, and moreparticularly, to a reciprocating rotary surgical instrument for cuttingsemi-rigid tissue.

BACKGROUND

Conventional arthroscopic surgical instruments generally include anouter tube and an inner member that rotates or translates axially withinthe outer tube. The outer tube and inner member may interact to createshear forces that cut tissue. This type of cutting is generally used tocut soft tissue, such as muscle, ligaments, and tendons.

SUMMARY

In one aspect, a surgical instrument includes a cutting member with animplement for cutting tissue, and a drive coupled to the cutting memberto simultaneously rotate and translate the cutting member in response toa force applied to the drive.

One or more of the following features may be included in the surgicalinstrument. The drive is configured such that the cutting memberreciprocates. The drive includes a drive member attached to the cuttingmember. The drive member includes a helical groove. The drive includes atranslation piece disposed in the groove such that rotary driving of thedrive member results in simultaneous reciprocation of the drive memberrelative to the translation piece.

In the illustrated embodiment, the drive includes an inner drive hubcoupled to the drive member. The inner drive hub defines a slot and thedrive member includes a key received in the slot rotary coupling thedrive member to the inner drive hub such that the drive member rotateswith the inner drive hub while being free to translate relative to theinner drive hub. The helical groove includes a left-hand threadedhelical channel. The helical groove includes a right-hand threadedhelical channel. The cutting member is attached to the drive member tomove rotatably and axially with the member.

The implement is a chamfered cutting edge at a distal end of the cuttingmember. The chamfered edge is a straight cutting edge. Alternatively,the chamfered edge is an angled cutting edge.

The instrument includes an outer tubular member. The cutting member isreceived within the outer member. The outer member includes a cuttingwindow disposed proximate to a tip of the outer member. The cuttingwindow is an opening in the outer member exposing the cutting member totissue. The cutting window has a U-shaped proximal end and asaddle-shaped distal end. The saddle-shaped distal end of the cuttingwindow includes a hook.

The translation piece includes a follower received within the groove anda sealing cap over the follower. The follower is free to swivel relativeto the sealing cap. The follower has an arched bridge shape. Thetranslation piece is coupled to the drive member such that thetranslation piece is disposed in the helical groove and swivels tofollow the helical groove as the drive member rotates.

In another aspect, a method of cutting tissue includes positioning anouter member such that tissue is located within the outer member,engaging the tissue with an inner member received within the outermember, and simultaneously rotating and translating the inner member tocut the tissue. One or more of the following features may be included.The translating is reciprocating. The outer member is orientedtangentially to the tissue.

In another aspect, a method of cutting tissue includes providing asurgical instrument having an outer member and an inner member receivedwithin the outer member for movement relative to the outer member, andapplying a tangential cutting force to the tissue with the inner memberto mechanically cut the tissue.

In another aspect, a method of cutting tissue includes applying atangential cutting force to tissue with a member, and mechanicallydriving the member to undergo simultaneous rotation and translation. Themethod may include that the translation is reciprocation.

The cutting edge of conventional arthroscopic surgical instruments, suchas rotary shears, have difficulty initiating a cut into semi-rigidtissue tend to bounce away from the tissue. Toothed edge geometrysomewhat ameliorates this problem because the “teeth” attempt to piercethe tissue to initiate a cut. However, the efficiency of using “teeth”is limited and the limitations are more evident when cutting largevolumes of semi-rigid tissue, such as meniscus or intrauterine fibroidtissue. The simultaneous rotating and reciprocating inner member of thesurgical instrument of the invention overcomes these difficulties. Thetangential approach to the tissue in the method of the invention limitsthe tendency of the instrument to bounce away from the tissue. Inparticular, the instrument and method provide a higher resection rate toshorten procedure length, during, e.g., fibroid and polyp resection.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features will beapparent from the description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1A is a side view and 1B is a cross-sectional view taken along1B-1B in FIG. 1A of a reciprocating rotary surgical instrument.

FIG. 2A is a top view, FIG. 2B is a cross-sectional view taken along2B-2B in FIG. 2A, FIG. 2C is a distal end view, and FIG. 2D is aproximal end view of the inner drive hub of the reciprocating rotarysurgical instrument of FIG. 1.

FIG. 3A is a top view, FIG. 3B is a side view, FIG. 3C is across-sectional view taken along 3C-3C in FIG. 3A, and FIG. 3D is aproximal end view of the helical member of the reciprocating rotarysurgical instrument of FIG. 1.

FIG. 4A is a top view, FIG. 4B is a cross-sectional view taken along4B-4B in FIG. 4A, and FIG. 4C is a distal end of the outer hub of thereciprocating rotary surgical instrument of FIG. 1.

FIG. 5A is an exploded view, FIG. 5B is a partial cutaway view, andFIGS. 5C and 5D are side views of the translation piece and the helicalmember of the surgical instrument of FIG. 1.

FIG. 6A is a side view, FIG. 6B is a cross-sectional view taken along6B-6B in FIG. 6A, and FIG. 6C is a top view of the follower of thetranslation piece of the reciprocating rotary surgical instrument ofFIG. 1.

FIG. 7A is a top view and FIG. 7B is a cross-sectional view taken along7B-7B of FIG. 7A of the cap for the follower of the translation piece ofthe reciprocating rotary surgical instrument of FIG. 1.

FIG. 8A is a top view and FIG. 8B is a side view of the outer member ofthe reciprocating rotary surgical instrument of FIG. 1.

FIG. 9 is a side view of the inner member of the reciprocating rotarysurgical instrument of FIG. 1.

FIG. 10 illustrates a reciprocating rotary surgical instrument of FIG. 1in use to cut tissue.

FIG. 11 is a side view of an alternate implementation of the innermember of a reciprocating surgical instrument.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

As shown in FIGS. 1A and 1B, a cutting device 100 includes a driving end110 and a cutting end 190. The driving end 110 is located at theproximal end of the cutting device 100. The cutting end 190 is locatedat the distal end of the cutting device 100.

At the driving end 110, there is an inner drive hub 130 with a drivecoupler 120, and an outer hub 140. The drive coupler 120 mounts into arotary driver (not shown), which turns the drive coupler 120 causing ahelical member 150 and the inner drive hub 130 to rotate. For instance,the rotary driver is Dyonics Power Handpiece, No. 725355. The innerdrive hub 130 with the drive coupler 120 is, for example, a component ofSmith & Nephew disposable arthroscopic surgical instrument, No. 7205306.The helical member 150 is located within the inner drive hub 120 and theouter hub 140. The helical member 150 and a translation piece 145 arecoupled together such that rotation of the helical member 150 causeslinear translation of the helical member 150, as described furtherbelow.

The cutting device 100 includes an elongated inner member 185 and anelongated outer member 186, as shown in FIG. 1B. The inner member 185 istubular with a hollow interior 184. The inner member 185 is fixed to thehelical member 150 for axial and rotary motion therewith.

The outer member 186 is also tubular with a hollow interior 187. Theinner member 185 is received inside the outer member 186. The outermember 186 is fixed to the outer hub 140 and does not move. The outermember 186 includes a tip 188, which is blunt, i.e., the corners arerounded. At the cutting end 190, the outer member 186 defines a cuttingwindow 170 through a wall 186 a of the outer member 186.

Referring to FIGS. 2A-2D, the inner drive hub 130 includes the drivecoupler 120, a lumen 136, an aspiration opening 132, and a slot 134. Thedrive coupler 120 extends from the proximal end of the inner drive hub130 and mounts in the rotary driver. Debris from the cutting end 190 ofthe cutting device 100 is aspirated through the aspiration opening 132.The slot 134 is disposed in a wall 131 of the inner drive hub 130. Theslot 134 is like a track along one side of the inner drive hub 130. Theslot 134 of the inner drive hub 130 is coupled with a key 152 of thehelical member 150 (see FIG. 4B) so that rotation of the inner drive hub130 causes the helical member 150 to rotate while allowing the helicalmember 150 to move axially relative to the inner drive hub 130, e.g.,the key 152 axially slides along the slot 134.

Referring to FIGS. 3A-3D, the helical member 150 of the cutting device100 is formed of a lubricious material in a tubular shape with a throughlumen 159. The inner member 185 is disposed within the helical member150 and fixed therein, for example, by epoxy, injection-molded, orover-molded plastic.

The helical member 150 includes the key 152 and two helical channels156, 158 disposed thereon. As shown in FIG. 3B, the key 152 is shapedlike a fin and is located at the proximal end of the helical member 150.The key 152 mates with the slot 134 of the inner drive hub 130.

The two helical channels 156, 158 are disposed on a distal portion ofthe exterior surface of the helical member 150. One helical channel 156is right-hand threaded; the other helical channel 158 is left-handthreaded. The pitch of the helical channels may be different or thesame. The length of the distal portion of the helical member 150 withhelical channels 156, 158 is longer than the length of the cuttingwindow 170. The helical channel 156, 158 are smoothly blended togetherat their ends to form a continuous groove so that there is a smoothtransition from one helical channel to the other helical channel at eachend of the distal portion of the helical member 150.

The helical member 150 and the inner drive hub 130 are mechanicallydriven by the rotary driver. The helical member 150 also moves in anaxial direction, e.g., reciprocates, as a result of the interaction ofthe translation piece 145 with the helical channels 156, 158, asdescribed below.

Referring to FIGS. 4A-4C, the outer hub 140 of the cutting device 100 isformed of hard plastic and does not move. An example of an outer hub isa component of Smith & Nephew disposable arthroscopic surgicalinstrument, No. 7205306, modified with a cutout 144 for receiving thetranslation piece 145. The cutout 144 is disposed within a wall of theouter hub 140, for example, centrally, as in FIG. 4B, and aligned withthe helical member. The translation piece 145 is located in the cutout144 of the outer hub 140.

As shown in FIG. 1B, the outer member 186 is disposed within the outerhub 140 and fixed therein by a coupling 144 using, for example, epoxy,glue, insert molding, or spin-welding.

Referring to FIG. 5A, the translation piece 145 includes a follower 145a and a cap 145 b. Having the two helical channels 156, 158 inconjunction with the slot/key 134, 152 coupling of the inner drive hub130 and the helical member 150, the rotary driver only needs to rotatein one direction and does not require reversal of the rotationaldirection upon the translation piece 145 reaching the end of one of thehelical channels 156, 158.

Referring to FIGS. 6A-6C, the follower 145 a includes a cylindrical head145 a 1 and two legs 145 a 2. As shown in FIGS. 5B-5D, the legs 145 a 2form an arch and rest in the channels of the double helix 156, 158formed in the distal portion of the exterior surface of the helicalmember 150. The arch of the legs 145 a 2 is dimensionally related to thediameter described by the helical channels 156, 158 of the helicalmember 150.

Referring particularly to FIGS. 5C and 5D, as the helical member 150 andthe inner drive hub 130 are mechanically driven by the rotary driver(not shown), the follower 145 a follows the helical channels 156, 158,swiveling as the follower 145 a smoothly transitions from helicalchannel to helical channel 156,158 at the ends of the distal portion ofthe helical member 150 having the helical channels 156, 158. Thecoupling of the follower 145 a to the helical channels 156, 158 causesthe helical member 150 to also translate. Thus, the inner member 185simultaneously rotates and reciprocates to cut the tissue.

Referring to FIGS. 7A and 7B, the cap 145 b of the translation piece 145covers the follower 145 a to provide a seal to allow sufficient suctionto remove aspirated debris. Also, the cap 145 b is a separate piece fromthe follower 145 a in order to allow the follower 145 b to swivel.

As shown in FIGS. 8A and 8B, the outer member cutting window 170 has agenerally oblong shape. The proximal end 172 of the cutting window 170is U-shaped and the distal end 173 has a saddle shape that forms a hook174. The distal end 173 is chamfered to provide a sharp edge. The hook174 pierces the targeted tissue to hold the tissue as the inner member185 cuts. Also, the shape of the cutting window 170 eliminates gallingbetween the inner and outer members 185, 186, and dulling of the cuttingedge of the inner member 185.

The cutting window 170 is disposed proximate to the tip 188 of the outermember 186. The cutting window 170 exposes the inner member 185 over alength L.

FIG. 9 shows that the inner member 185 is generally tubular with hollowinterior 187. Aspiration of debris occurs through the hollow interior187 of the inner member 185, and through the lumen of the helical memberto the aspiration opening 132 of the inner drive hub 130. The distal end183 of the inner member 185 is chamfered to a sharp edge 187 forcutting. The inner member 185 simultaneously rotates about its axis andtranslates along its axis to cut tissue. The cutting surface of thedistal end 183 of the inner member 185 shears the tissue. For example,referring to FIG. 10, the cutting device 100 is placed tangentiallyagainst the targeted tissue such that the cutting window 170 exposes theinner member 185 to the tissue. As the inner member 185 rotates andtranslates, as shown by the arrows, the tissue within the cutting windowcatches on the hook 174 to initiate the cut and then the cutting edge183 of the inner member 185 shears the tissue as the inner member 185advances to cut the tissue. The cut is completed as the cutting edge 183of the inner member 185 advances beyond the hook 174 of the cuttingwindow 170 within the outer member 186.

FIG. 11 shows an alternative implementation of the inner member. Thedistal end 283 of the inner member 285 may be angled to a chamferedpoint so that the cut in the targeted tissue is initiated on one sideand then extends across the width of the tissue. Similarly, when thecutting device is placed tangentially against the targeted tissue, therotating and translating inner member 285 shears the tissue to be cut.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made. For example,instead of a double helical channel, the helical member may include asingle helical channel with a retractable follower and spring, orpossibly, attraction and repelling forces of magnets or a solenoid couldenable the rotating and reciprocating movements. Also, alternatively,the inner and outer members may have a cross-sectional shape other thancircular. Additionally, the shape of the hook of the outer member may bemodified in order to improve grasping of the tissue or grasping a largervolume of tissue. Accordingly, other implementations are within thescope of the following claims.

1. (canceled)
 2. A driving assembly of a surgical instrument,comprising: a drive coupler configured to receive a rotational input; ahelical member operably coupled to the drive coupler such that rotationof the drive coupler rotates the helical member, the helical memberdefining a helical groove having a first threaded helical channel and asecond threaded helical channel, the first and second threaded helicalchannels blended together at their ends to form a continuous groove suchthat there is a smooth transition from the first threaded helicalchannel to the second threaded helical channel; and a translation pieceengaged within the helical groove such that the helical member providesboth a rotational output and translational output in response to therotational input.
 3. The driving assembly according to claim 2, whereinthe drive coupler is adapted to connect to a rotary driver configured toprovide the rotational input to the drive coupler.
 4. The drivingassembly according to claim 2, wherein the helical member is adapted toconnect to a cutting member to provide the rotational output and thetranslational output thereto.
 5. The driving assembly according to claim2, wherein the first threaded helical channel defines a right-handedconfiguration, and wherein the second threaded helical channel defines aleft-handed configuration.
 6. The driving assembly according to claim 2,further comprising an outer hub at least partially housing the helicalmember and the translation piece therein.
 7. The driving assemblyaccording to claim 6, wherein the drive coupler extends proximally fromthe outer hub.
 8. The driving assembly according to claim 6, wherein thetranslation piece extends through a cut-out defined within the outer huband is longitudinally fixed within the cut-out.
 9. The driving assemblyaccording to claim 2, wherein the helical member is operably coupled tothe drive coupler via a key-slot arrangement rotationally coupling thedrive coupler to the helical member and permitting translation of thehelical member relative to the drive coupler.
 10. The driving assemblyaccording to claim 2, wherein helical groove extends at least two fullrevolutions about the drive member.
 11. The driving assembly accordingto claim 2, wherein the translation piece is configured to swivel whenmoving between the first threaded the helical channel and the secondthreaded helical channel.